From the main menu of the Apple TV, select the green Hulu Plus icon and click on the center Select button on your Apple remote.
Next, choose the log in option that best fits.
If you are already a Hulu Plus subscriber and are having trouble accessing your account, please go to our Forgot Password page to reset your password or find the email address you used to sign up with. If you initially created your Hulu Plus subscription on your Apple TV, you are being billed through iTunes and can click the Purchased through iTunes? Restore button on the main screen of the Hulu Plus app. You will then be able to log in with your Apple ID to access your subscription (to verify if your Hulu Plus subscription is being billed through the iTunes store, please see this help article).
For some basic troubleshooting suggestions, go to: Settings > General > Troubleshoot
If necessary, please also try the following: